Servo pattern for dedicated surface track following servo systems

Abstract

A disk for use in a dedicated surface track following servo system has a plurality of radially spaced circumferential tracks on which synchronizing, position, and track region identifying transition pairs are recorded together with guard transition pairs between the synchronizing and position transitions pairs and between the position and track region identifying transition pairs. The guard and position transition pairs each bridge two adjacent tracks and are separated radially and circumferentially from track to track in repetitive staircase fashion.

The invention claimed is: 
     
       1. For use in dedicated surface track following servo system, a disk having on one surface a plurality of radially spaced circumferential servo tracks on which magnetic patterns are pre-recorded, and a positionable magnetic pattern sensing transducer having a width twice the width of a servo track for simultaneously sensing the magnetic patterns in two adjacent servo tracks whereby position errors may be generated when said transducer is not centered on the boundry between selected adjacent servo tracks, each of said servo tracks comprising a series of servo cells in each of which is recorded a pattern comprising in turn circumferentially spaced synchronizing information, repetitive servo position information, and track region indentifying information, and   wherein between said synchronizing and said servo position information, and between said servo position and track region identifying information, guard information is recorded in selected servo tracks, to avoid disruption of pattern uniformity.   
     
     
       2. For use in a track following servo system as recited in claim 1, said recorded information comprising magnetic transition pairs, and said synchronizing pairs extending radially over all tracks. 
     
     
       3. For use in a track following servo system as recited in claim 2, said servo cells each comprising a plurality of subcells containing only repetitive servo position transition pairs. 
     
     
       4. For use in a track following servo system as recited in claim 3, said servo position transition pairs in a subcell extending over two servo tracks and being radially separated by two servo tracks. 
     
     
       5. For use in a track following servo systems as recited in claim 4, said guard transition pairs extending radially over two servo tracks and being radially separated by two tracks. 
     
     
       6. For use in a track following servo system as recited in claim 5, said guard and servo position pairs occupying sites which are radially and circumferentially spaced from track to track in repetitive staircase fashion. 
     
     
       7. For use in a track following servo system as recited in claim 4, said transducer output being characterized by positive and a negative going signals having a uniform characteristic whose peak amplitudes are a function of the spacing between transitions of a pair and between transition pairs. 
     
     
       8. For use in a dedicated surface track following servo system as recited in claim 1, said disk having another surface parallel to the servo track surface containing closely spaced circumferential data tracks on which data may be recorded and read, said data track centerlines being opposite the boundries between adjacent servo tracks.